Certain passenger vehicles include passenger seats having a seat back that can be folded to a generally horizontal position. Typically, the seat back is formed of a relatively rigid plastic material, or covered with a relatively taut, flat fabric providing a generally flat surface. As such, when the seat back is folded to the horizontal position, objects can be placed on the seat back. Unfortunately, if the vehicle moves or shifts, or if the objects are otherwise caused to move, the objects tend to slide, roll or fall from the seat back. Accordingly, the seats do not provide a very useful area for storing or resting objects when their seat backs are in their horizontal position.